Unstatesmanlike noises

THE 5.7-litre V8 in my WK Holden Statesman emits a dreadful clatter on start-up after being garaged overnight. It seems to me that it is starved of oil until the pump ``catches up''. Thereafter, a gentle ``clack, clack'' noise is audible at idle speeds and never goes away. At its six months' service the dealer stated that ``on inspection there were no unusual engine noises detected''. I would appreciate your view as to whether such noises are not uncommon with this engine before I revisit the matter with the dealer.